1. Field
One embodiment of the present invention relates to an optical disk device and control method in which software is used for digital control of a laser light source.
2. Description of the Related Art
Recently, the integration density of digital ICs has been markedly enhanced. Along with this, an attempt is made to reduce the cost by integrating control hardware of an optical disk device as a digital IC and applying software for digital control of a laser light source.
In a general optical disk device, a control processor is provided as a digital IC that generates setting data items such as a laser driving current value, operation mode and parameters of a recording waveform and transmits the above data items to an automatic power control circuit in a serial form. In the automatic power control circuit, a laser driver that drives a laser light source such as a semiconductor laser element and a light amount detecting module that detects the light amount of laser light emitted from the laser light source are provided, and the operation setting of the laser driver and light amount detecting module are made based on the setting data items. The setting data may vary due to an influence of electromagnetic noise and static electricity applied from the exterior during the transmission. If the setting data set in the varied state is received by the automatic power control circuit, a malfunction occurs in the laser driver and light amount detecting module. For example, if an excessive amount of laser driving current flows into the semiconductor laser element of the laser light source as a result of the malfunction, this causes the semiconductor laser element to be destroyed.
There already exists a technique for checking data transmitted to the automatic power control circuit as recording information with respect to an optical disk (for example, see Jpn. Pat. Appln. KOKAI Publication No. 2003-78203). With the above technique, a microcomputer (control processor) performs a process of transmitting data to the automatic power control circuit, a process of acquiring data stored in the automatic power control circuit, a process of comparing the transmission data with the stored data and a process of permitting the automatic power control circuit to record the stored data when it is confirmed from the comparison result that the stored data is correct.
However, when the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-78203 is applied to the above transmission process of the setting data, the time required for performing the 4-step process cannot always be attained thus the operation setting in the automatic power control circuit tends to be delayed. Further, in Jpn. Pat. Appln. KOKAI Publication No. 2003-78203, a control operation of delaying the data transmission speed is performed when non-coincidence of data items occurs, in order to obtain a margin for data communication timing. Thus, the operation setting tends to be delayed due to the control operation.